Rotisserie Chicken and Stuffing Casserole

Preheat oven to 375 degrees F (190 degrees C).

Spray a 9x13-inch baking dish with cooking spray.

Bring water and 1/4 cup butter to a boil in a saucepan; stir in stuffing mix.

Remove saucepan from heat, cover, and let sit until water is absorbed, about 5 minutes.

Fluff stuffing with a fork.

Heat 1 tablespoon butter in a skillet over medium heat; cook and stir onion and celery until softened, 5 to 10 minutes.

Mix cream of chicken soup, sour cream, and cream of mushroom soup together in a bowl.

Spread shredded chicken into the bottom of the prepared baking dish.

Layer onion mixture over chicken and season with salt and pepper; top with soup mixture.

Spread stuffing over soup mixture layer.

Bake in the preheated oven until lightly browned and bubbling, about 1 hour.